The present invention relates to a resin layer formation method, a semiconductor device and semiconductor device fabrication method.
For the large integration and large density of semiconductor devices, etc., it is advantageous to form multilayer interconnections.
However, when a multilayer interconnection structure is formed by simply laying interconnections and insulation layers (inter-layer insulation films), large steps, i.e., large concavities and convexities are formed in the surfaces of the insulation layers.
It is difficult to micronized interconnections at a small pitch on insulation layer having large steps. Accordingly, it is very important to planarize the surfaces of the insulation layers.
As a technique for planarizing the surface of an insulation layer, CMP (Chemical Mechanical Polishing) is widely known.
However, the planarization by CMP causes relatively large costs. When a thickness to be polished is as relatively large as several micrometers, the planarization takes long time.
As a technique for planarizing the surface of an insulation layer, grinding with a grinding wheel is also known.
However, in grinding with a grinding wheel, when the material of an insulation layer is a resin, the resin stays on the surface of the grinding wheel and clogs. The grinding with a grinding wheel is thus unsuitable to planarize a resin layer. In grinding with a grinding wheel roughness of the micron order is caused in the surface of a ground insulation layer. When electrodes and an insulation layer are ground with a grinding wheel, fins are often formed on the surface of the ground electrodes, or the insulating material often stay on the surface of the electrodes.
On the other hand, a technique for forming a resin layer on a substrate and cutting the surface of the resin layer with a cutting tool is proposed (see Patent Reference 1). In the cutting with a cutting tool, a resin layer of a several micrometers-thickness can be cut once, and even when a relatively large thickness is cut, the planarization can be done in a relatively short period of time.
Following references disclose the background art of the present invention.
[Patent Reference 1]
Specification of Japanese Patent Application Unexamined Publication No. 2005-12098
However, when a resin layer containing a filler (substance) of an inorganic material, such as silica or others, is cut with a cutting tool of diamond or others, the filler contained in the resin layer rapidly abrades or breaks the tip of the cutting tool. When a resin layer and electrodes are cut with a cutting tool having the tip abraded or broken, fins are formed in the cut electrodes, the resin stays on the surfaces of the electrodes, or the surface of the resin layer and the surfaces of the electrodes are damaged.